Method of and apparatus for elevating liquids by a multilift uniflow airlift system



May 12, 1925. 1,537,264

E. M. ROGERS METHOD OF AND APPARATUS FOR ELEVATING LIQUIDS BY AMULTILIFT UNIFLOW AIRLIFT SYSTEM Filed March 24, 1923 4 Sheets-Sheet l il M v L [nae/afar: Zola/WW5,

May 12, 1925.

M. ROGERS METHOD OF AND APPARATUS FOR ELEVATING LIQUIDS BY A MULTILIFTUNIFLOW AIRLIFT SYSTEM 4 Sheets-Sheet 2 fi zverlior:

Edwin MR gens,

Filed March 24, 1923 By his day,

May 12, 1925. 1,537,264

METHOD OF AND APPARATUS FOR ELEVATING LIQUIDS BY A MULTILIFT E. M.ROGERS UNIFLOW AIRLIFT SYSTEM Filed March 24, 1923 4 Sheets-Sheet 5 Jo 3ol T 3 a a F 5 I 7a 3 3 Z 6 Z r 5 r rFWF ens;

4 6 7T 3m 5m m u M A Y B S D I U Q m S m H A w RL E m E Q. U T A R A P PA D N A 5 F 20 D 10 .H Um V- M UNIFLOW AIRLIFT SYSTEM Filed March 24,1923 4 Sheets-Sheet 4 In lrenior: Edwin I! I? gens;

Dy in)! fli'ay,

Patented May 12, 1925.

UNITED STATES PATENT OFFICE.

EDWIN M. ROGERS, OF NEW YORK, N. Y.

METHOD 01* AND APPARATUS FOR ELEVATING LIQUIDS BY A MULTILIFT UNIFLOWAIRLIFT SYSTEM.

Application filed karch'24, 1923. Serial No. 627,405.

T 0 all whom it may cmwern:

Be it known that I, EDWIN M. Roonns, a citizen of the United States,residing in New York, in the county of New York and State of New York,have invented certain new and useful Improvements in Methods of andApparatus for Elevating Liquids by a Multilift Unifiow Airlift System,of which the following is a specification.

The resent improvements relate to the art of e evating liquids by meansof the airlift, and to improved methods and apparatus whereby to effectthe air-lifting operation in a continuous and economical manner, andespecially by an improved multi-stage operation under the control of aninteractive regulation and thereby secure a highly effective mode of"action, and an adaptability for successful use under a wide range ofconditions, and for practically and rapidly elevating liquids to unusualheights in proportion to the initial submergence and while greatlyreducing the losses,especially the waste of power, normally and hithertoresulting from the use of the air under a high degree of compression.

A leading object of the present invention is to furnish a method ofair-lifting liquids whereby the liquid to be elevated may be initiallyreceived in a stream at the lower end of a primary uptake pipe, and thenbe conducted through any required number of successive elevation-stagesto an outlet for final discharge, and be so conducted while maintained(throughout its path or course) in the form of a continuous stream notsubjected, first, to dispersion. and then to reformation while thestream, in passing through successive uptake stages, is subjccted tosuccessive aerations and de'aerations. Since, by means of this method,the flow of liquid continues in a highly constant and uniform mannerhitherto not practically attainable, I have herein designated thispeculiar and continuous flowage of the liquid as a uni-flow stream.

A further object is to provide a liquidelevating appartus in which thedescribed uni-flow stream may be conducted in a continuous stream-formthroughout its entire path or route from inlet to outlet, and be thereinforwardly impelled by successive submergence-effects combined andcoactive. with corresponding aerations and de-aeration stages; andwhich, for realizing this method and result, shall subject the uni-flowstream (continuously while in operation) to the controlling effect of aplus-atmospheric pressure at all points in the said path thereof, and,also, to an interactive re ulation of flowage and of submergence-eectsin all (or in any desired plurality) of said successive stages.

A still further object is to furnish such an apparatus provided withmeans for obtaining said plus-atmospheric pressure, and an effectiveinteractive regulation by the aid of a method of energy-conversion,whereby the kinetic-energ of a spouting column may be utilized at eacfi(or at one or more) of the de-aeration stages, for thereby producing asuper-head pressure in an outlet channel of, and at the junction of, anuptake column with a next following and down-flowing submergence column,and for thereby also forming a liquid-column super-head supplemental toan otherwise normal submergence-head, so that at each down-turn por tionof the uni-flow stream the movement thereof will take place by acontinued stream-form flowage and while maintained under the super-headpressure.

A further object is to provide an airlift system comprising successivesingle airlifts (whether these are two or more in number) which shall bearranged in the system, and shall coactively operate as airlift pairshaving the airlifts thereof connected for interactive regulation; and,for thus purpose, also to combine and connect the uptake column of onesaid airlift (this column being longitudinally elastic by reason of itsaeration) with the submergence column of a next following airlift, (thissubmergence column being, normally, longitudinally non-elastic owing toits relatively non-aerated condi- I tion), and so provide, (ashereinafter explained), for a time-interval to occur between certain ofthe inter-regulative functions, whereby to obtain a highly effectiveconjoint regulation as between a super-head portion of the submergencecolumn of one airlift and a super-head ressure in a combined de-aeraterand kinetic-energy converter of a preceding single airlift of thesystem.

It is also a further aim and purpose of the present invention so toemploy the numerous advantages peculiar to said method, and so toorganize and operate the apparatus as a whole and in detail, as tominimize the losses hitherto normally incident to the airliftin methodand to improve the character the cooperation and functioning of themethod and apparatus, for thereby securing an aggregate efliciency, anddependability of action, whereb this method may besubstituted,practically and with commercial advantage as to operatingcost and maintenance,-for the ordinary and much more expensive pumps orlike machines for either temporary or permanent use in rais- I byitself, but will operate together conjointly and in an interactive andinterregulativemanner, and thereby function as a single apparatus havingcontinuity of organization and action.

Also, one object is to furnish an improved rimary airlift, or singlesystem-member, or use as one member of the described airlift pair, andto provide this primary member with a structural arrangement or meansconstituting a combined de-aerator and kinetic-energy converter, whereban initial uptake column of aerated liqu1d,during a normal operation ofthe system,-shall be laterally enclosed throughout the entire heightthereof, within a conduit which includes an upper conduit-portion orlength wherein the de-aeration is normally effected in conjunction witha utilization of "the kinetic-energy of a spouting column to form andmaintain (during normal operation) a super-head pressure transmittableas a contlnulng force and with a plus-atmospheric pressure, to a nextsucceeding airlift memer of such a pair, and thence in the same mannerto a next following airlift of a multiair system. Thus, as hereinaftermore ully' explained, the apparatus comprises means for transforming thekinetic energy of the discharging water and airinto pressure and therebyconserving, or restoring, a part of the head otherwise lost; andtransforming into actual head such energies as are latent in, or resultfrom, the disturbances incident to the de-aeration process and to thetransferring of the liquid from one airlift-member to another of them ina multi-stage system.

A further object is to provide a peculiar and perfected organization ofthe said appai ratus and elements thereof, in which those elements,including the several conduit members appurtenant to the apparatus,shall be so connected into one continuous but multistage system, andshall be so coactive in this system for the inter-regulative control ofthe operation thereof, that the liquid may be air-lifted to relativelygreat elevations by short stages comprised in the single and continuousuni-flow stream, and shall thus operate with an economy incident to theuse of low-pressure air, and also so operate without the loss ordiscarding, at any point, of any increment or residue of un-utilizedair-pressure, and without the employment or aid of anymechanically-operable floats or valves, or other movably-actingregulators or stream-controlling devices, whether or not adapted fordirectly or indirectly affecting either pressures or stream-flow.

While the various phenomena involved in or incident to the operation ofthe system, or to the operation and interactive regulation of theairlifts comprised therein, or to the several components and devicesappurtenant to those airlifts, may not as yet, or in all respects, befully known or understood, nevertheless, from a considerable experiencewith airlifts as employed in mines, and from special investigations andpractical tests of the present improvements, it is believed that thefollowing description properly explains the nature and mode of action ofthis unitary airlift system and of the several elements thereof, inconnection with the accompanying drawings, in which Figure 1 is aside-view, or elevation (assumed to be drawn mainly insection)illustrative of a two-stage airlift system arranged and operable inaccordance with the present invention. In this view, for con- .venienceof illustration, (and following a conventional practice), the longertubes and conduit members are shown greatly reduced in length inproportion to their diameters, as compared with the relative lengths andsizes thereof heretofore more commonly used; this expedient is deemed tobe necessary in order to more clearly represent the relations of theseveral elements in a preferred organization thereof. For instance, thediameter of ipe B is here shown having a diameter 0 nearly one-twentiethof its length, Whereas in practice said diameter often ma be only two tofour inches, though 1n some 1 instances very much larger,--while almostany length may be used; lengths of from fifty to one hundred feet aresometimes employed, depending upon the conditions and requirements inany particular instance.

Fig. 2 is a side-view similar to Fig. 1 (but drawn on a smaller scale)for showing the same general arrangement when this is extended into athree-stage system having the component air-lifts thereof positioned,equipped and connected for an automatic and interactive regulation. 7

Fig. 3 is a side view analogous in arrangement to Fig. 2, for more fullyillustrating the method of operation of the system and the principlesthereof; and, for explaining the several coactive means and functionswhereby there is obtained an inter-regulative control which extendsthroughout this multi-stagc apparatus.

Fig. 4 is an enlarged and more complete view of the upper portion of aprimary airlift of the form shown in the preceding views, andillustrates certain relations and phenomena as hereinafter explained,regarding the spouting-column and the peculiar method and means providedfor utilizing the kinetic energy thereof while maintaining a uni-flowstream, and whereby said upper portion becomes an energy-converter andoperates in the multi-stage system as an economizer-regulator.

Figs. 4, 4", 4 and 4 are a series of diagrams supplementing Fig. 4, andfurther illustrate functions hereinafter explained in connection, moreespecially, with Figs. 3 and 4.

Fig. 5 illustrates how one detail of the apparatus may be modified inways and for purposes as hereinafter set forth.

Similar reference characters designate, or indicate like parts or lines,in all the views.

In the arrangements of air-lift apparatus shown in the drawings,successive uptake columns are desi nated. in the order of their action,by B 13 and B, respectively; and, the respective submcrgence containerstherefor are designated by D 1) and D. This container, or receptacle,for uptake column B may consist, as here illustrated, of a pit, or well,B, into which the liquid is collected and in which said column B extendsdownwardly in a manner commonly employed in locating ordinary air-liftin mines; the height of the submergence is here indicated by thewater-surface line 4. For the uptake columns B and B submergenrecontainers in the form of tubular columns, as D and D", are deemed to bepreferable, these being suitably positioned and connected substantiallyas indicated.

Said uptake column, or pipe, B, is considered to be the primary uptakecolumn, since this initially receives all the liquid to be elevated; andwhen deemed to be desirable, the liquid may be supplied to this column,ii. by a tubular form of submergcnce container, such as l), which thusbecomes an equivalent or substitute for this purpose, of the shaft orwell I).

In practice, the several tubular columns, and the accessory devicestherefor, may be supported by any suitable means, such as foundationsand retaining members (not herein shown), thesebeing arranged andconnected in accordance with principles and methods already well-knownin the art of pumps and air-lifts; but, to simplify the illustration ofthe principal elements and features, those ordinary means are not hereinfully shownor described. r

In some instances a single arrangement of the air-lift may be used, thiscomprising a primary uptake column, as B, and having suitablesubmergence-supplying and airsupply means therefor. This single airlift,when equipped and arranged 'in accordance with the present invention,will be provided at the upper part of its said uptake column, with anenergy-converter, and, preferably, with a supplemental-head-conservingmeans, these two devices being illustrated, each in a preferred formthereof, in Fig. 4 and Fig. 5, respectively, and hereinafter more fullyexplained.

enerally, however, in order economically and practically to meet themore usual present-day requirements, it is important, and oftennecessary, to employ a plurality of airlifts arranged in series, andthereby deliver the liquid to a considerable elevation. In Fig. 1, thepresent improvements are shown thus applied to a two-stage system inwhich the liquid is conducted in a uni-flow stream. In this arrangement(Fig. 1), the submergence column, or well, D and connected uptakecolumn. B are comprised in the first air-lift; and, the tubularsubmergence column I) and connected uptake column B are comprised in thesecond air-lift. These two air-lifts, each connected and furnished forco-active and inter-regulative operation, together constitute oneair-lift pair, as hereinafter more fully explained. V

The system illustrated in Fig. 1, is shown in F ig. 2 extended into athree-stage system, this comprising three air-lifts, or airlift-membersof the series. Each of these air-lifts comprises an uptake column and asubmergence container therefor; and, all are connected and furnished forcoactive and inter-regulative operation similarly as described inconnection with Fig. 1. As in Fig. 1, the column B is here the primaryuptake column of the first airlift-pair, and the submergence is shown tobe obtainable by extending the column B downwardly in theliquid-collecting well I) to a proper disstance below the line 4, which(as in Fig. 1) represents a normal water level. Also, in Fig. 2. theentire m-ulti-stage system is indicated, by the walls 5 and 5', as beinglocated mainly below a groundsurface line 6 and in a shaft or chamberanalogous to those common to mines and quarries.

In the present multi-stage system, the entire apparatus may be regardednot merely as a series of individual air-lifts peculiarly connected forcoactive operation, but also as a single air-lift in which one stream issuccessively actuated, and in which successive portions of the air-liftstructure so control ,the.operation of successive portions,respectively, of said single stream, that these stream-portions becomethe operating instrumentalities and coact with and upon each other foreffecting the inter-regulative control of all the stream-portions, andthus of the stream as a whole.

Before proceeding further with detailed explanations of the foregoingfeatures and of their modes of interaction for effecting theinter-regulative function, some incidental matters should be noted Thefunction of the air bubbles being to lighten the liquid content of theup-take column, so that the weight thereof will be over-balanced by theweight of the submergence head, it is obvious that any available gasesmay be used in place of atmospheric air, and hence it is tobe'understood that the 'term air is herein employed as a generic termfor designating the air or other gas which may be in any given instanceavailable for use, or be used. in effecting the necessary reduction inthe weight of the fluid contained within a given length of an uptakepipe.

The aerated uptake stream on passing above the upper end of an uptakepipe, issues as the spouting column, and the process of de-aeration isonly completed at the upper end of this column, and within theenergy-converter apparatus, as K.

The term spouting head is intended to refer to the height of liquidcontained in the spouting column, if this liquid should be considered,or measured, by the reaction effect or pressure thereof downwardly atthe level of the discharge end of the uptake pipe. For instance,supposing that the spouting colmun (see Fig. 4) might have I an extremeheight of seven feet, but contain such a quantity of air so distributedtherein as to have a pressure effect at said pipe-end level only equalto a liquid column three feet in height, then this head of three feetwould be the spouting head, and would represent the pressure effecttransmissible for producing a supplemental head in the Tq bmergencecolumn of a next following air- In the practical operation of anordinary airlift series, sometimes the working conditions will bemodified in such a manner or to such an extent as to change the rate ofupflow,-that is. the rate of action. or discharge,and thus for "a timecause some one of a series of the ail-lifts to have an undue excess ofaction as compared (at such a moment) with another of them. Thesevariations, sometimes, heretofore. have been regulated by means ofmechanically-operable govermng devices applied to the several componentair-lifts of such a series. the present system, however, no suchgoverning devices are required, owing to the interactive control bywhich the heads and pressures are now made conjointly operative andinter-regulative, for thereby effecting the necessary control by anauto-governing action which extends to the system as a whole, and alsoapplies to each of the individual airlift-members thereof. These resultsare now attained, as hereinafter explained, by means of a combination ofcoactively-operating structural features which has the function of anoscillation governor, said features being arranged for restricting,orrendering less active than otherwise would be normal,-such oscillationsof pressure and flowage as may occur from time to time, in either one orboth of the airlifts of an airlift pair, and thereby accelerate theprocess of balancing, or re-balancing, an unequal operation ofsuccessive airlifts, (or of an pair of them), whenever either one of Suei a pair may have been materially changed in its rate of action relativeto the other.

The several uptake pipes,these being uptake-stream containers,aredesignated, (in Figs. 1, 2 and 3), by B 13 and B for indicating therespective positions in the system of this series of similar members, ofwhich one may be designated individually but without choice, as the pipeor column B. In like manner the submergence columns may be designatedindividually but without choice, as column D; and, the

.members K K K, may be so designated by K, and especially in connectionwith Figs. 4 to 4" inclusive. On the same principle, any one of theaeration nozzles may be referred to as nozzle N, and any airsupply pipetherefor, as pipe t; and similarly, any of the columns-connectingconduits, or ports p, p", may be designated by P whenever this may besufficient, or consistent in view of the context; this method may alsobe extended to other details common to a plurality of the air-lifts ofthe system. 1

In Fig. 1, the uptake column, B, is shown provided with astream-conductor pipe, P

shown in a sub-surface position, for thereby] transferring the uni-flowmain-stream for one to a next following airlift while this stream ismaintained at all points under a plus-atmospheric pressure. Thisplus-pressure, in practice, preferably should be greater than thepressure-variations liable to occur within the uptake and submergencecolumns by 01' during the coactive operation thereof; hence,ashereinafter explained,the submergence super-head should be of suflicientheight and quantity for effecting this result. Above, but adjacent to,said stream-transferring conduits or passageways, P}, P said uptakecolumns B B are shown each provided with an apparatus having thefunction of an energy-converter, as K and K respectively, each of whichforms the upper-end portion of an uptake column. This device, orconverter, has the function of a de-aerator, and operates to produce thesubmergence superhead, as 72 a preferred form of the apparatus beinghereinafter more fully explained, particularly in connection with Fig.4.

The uptake columns, B B B are shown in the accompanying drawings asbeing each provided at the lower end thereof (see Figs. 1 and 2) with anaeration device, or nozzle; thus the latter term is here usedgenerically. These aeration devices, (whether or not having the usualform of a nozzle), are symbolically indicated at and by N, N and Nrespectively, and in practice any of the well-known kinds ofstream-aerating devices, or air-lift nozzles, may be adapted andemployed for the present purposes. The nozzle at N operates to initiallyaerate the stream when this is entering column B, and A the nozzles at Nand N operate to re-aerate the same stream (subsequent to a de-aerationthereof) at successive points in the uniflow course, or path thereof. InFig. 3, these several nozzles are presumed to have effected suchaeration (each at its respective position) at'and upwardly from thelines 7 7, 7 respectively (Figs. 1 and 2).

For the purpose of supplying the air to the nozzles, the presentair-lift system may comprise, as an element thereof, any of thewell-known arrangements of air-supply apparatus such as already employedin ordinary air-lifts. For instance, as indicated diagrammatically inFig. 1, the uptake pipe, or column, may be suitably air-supplied bymeans of some ordinary air-compressor, as of suitable location andcapacity, and which may be connected by air-distributing pipes t t, tothe aeration devices or nozzles at N N N, for the uptake columns 13. B Brespectively. These air-distributing pipes are shown supplied, in Fig.1, by a main pipe, t, leading from compressor C; in Figs. 2 and 3, thepipe t is supposed to come from an air compressor not shown in theseviews. For regulating the action of the several nozzles said air supplypipes may be each provided (at some. or any, convenient point therein)with an ordinary flow-adjusting valve or regulator, as ind cated at V V(Fig. 1), respectively; also the compressor, or a pipe as t, therefrom,may have a main-valve, as at V, whereby to regulate, and to let on orcut oil, the whole air-supply at once. However, in some instances thesevalves may be omitted (as for instance in Fig. 2) if the pipes areample, the nozzles sufficiently uniform, and each 7 nozzle accuratelylocated at a proper relative elevation. i

For convenience of description, and to facilitate elearness ofillustration, the several principal members of the airlift pair havebeen shown in Figs. 1, 2 and 3, arranged side by side and at relativelyconsiderable distances apart, but it should be understood that inpractice, whenever found to be desirable, the several members, andespecially the uptake pipes B B and the submergence columns therefor,may be placed close to each other, or even more widely apart, accordingto the conditions attending any particular location or the preference ofthe constructor. One effect. evidently, of placing pipe B and saidcolumn D close to each other, is to shorten the distance through whichthe counter-flow stream has to travel in passing from the tie-aerationchamber, as K laterally through port P and into said column D anillustration of one such close form of assemblage is shown in the smallsectional side view, Fig. 5.

By extending this uniflow system from a 100 single airlift-pair, as inFig. 1, to includethree successive air-lifts, as in Fig. 2, a furtherand important improvement is thereby accomplished, since, in this moreextended system,-the plurality of three coactively- 105 connectedairlifts not only comprises three column pairs (each forming oneair-lift), but also comprises a plurality of airlift pairs.

For instance, in Fig. 2, (also in Fig. 3), 110 the three single airliftsare arranged first, into two pairs, and these pairs are arranged withone air-lift member common to both pairs. The primary airlift D B isarranged and connected for delivering liquid 'to a second airlift D Bthat in turn, de-

livers the same liquid to a third airlift, D B Thus the series of threeairlifts is here shown arranged in two successive pairs, in which thesecondary airlift, as D B of the first pair is also the primary airliftof the second pair; all three of these airlifts are herein indicated asbeing arranged,in this instancefor operation by air of the samepressure. Also in this triple system, there are two of theenergy-converter apparatuses which are also herein described anddesignated as a combined energy-economizer and oscillation governor.These two apparatuses, as K K are shown coactively connected each withother through an intervening uptake column, as B (Fig. 2), which isoperated by a submergence, as D that is supplied from said precedinuptake column 13, and is in part regulated by means of the first of saidcombined apparatuses; this auto-governing mode of action (heretoforementioned) is hereinafter more fully explained.

In said triple-arrangeient of Fig. 2, each of the uptake columnsoperates under a different condition from the other two. In the firstairlift, said column B is supplied from a normally fixed submergencelevel, as 4, and discharges against a spouting-column head (in column Kthat is subject to a governing action; in the second airlift, the uptakecolumn, B is supplied from a submergence column D which is subject to avariable but automatically-regulated pressure or head, and dischargesagainst a spouting-column head, (in de-aerator column K in the samemanner as said column 13, just described; and, in the third airlift, theuptake column, B is supplied by and from a submergence column, Darranged and operating similarly as the column D just described.

Thus the said series of airlifts, while each have distinctly differentoperating relations from the others, are interactive and adjunctive eachwith the other two, and therefore are subject, individually and as asystem or series, to the aforesaid auto-governing action. Each saidairlift of the system, thus may be said to have an individual andprimary mode of action normal to its own features and proportions; next,the successive airlift pairs have each a mode and ratio of action, oroperation, which may be said to comprise those individual actions plus avarlation arising from their interconnection, whereby a change ofoperating condition obtaining in one member of said pair, acts from timeto time, to accelerate or retard the action or ratio of operation of theother said member of the pair. This complexity of the relations andfunctions, is further increased in the present series-system, by theinclusion therein of a plurality of the sensitive and quick-actionapparatuses K, each operating as a combined energy-economizer andoscillation-governor.

In the three-stage system shown in Fig. 2 (also in Fi 3), the secondair-lift of the series may lie said to be, and is herein regarded asbeing, one form of a stream-impelling connector for receiving theuni-flow stream from the first air-lift and transmitting this stream (asan unbroken mainstream) tothe terminal air-lift (here the third one) ofthe system. Said intermediate stream-impeller is also here shown fittedand proportioned for operation as a second airlift of the system, andfor being operated by the same air-supply pressure andsubmergence-efl'ect as employed in the first air-lift column, B, andinthe third air-lift column, B, of the system.

However, this three-stage system may be arranged in some instances forusing such an air-lift form of intermediate impeller when this isproportioned for elevating the stream through a different proportionaldistance, or height. This arrangement of the system to use unequal'liftsfor successive and coactive airlift-members, will be obvious withoutbeing herein specially illustrated, and it may be so used advantageouslyin various locations. In such an instance, it is necessary, of course,that the successive uptake columns, respectively, shall each be provided(or connected) with means for suitably regulating the pressure andvolume of the supply of air thereto; for this purpose an ordinaryarrangement of compressor,

pipes and valves, (such for instance, as

herein described in connection with Fig. 1), will usually be ample forsuch requirements.

When the liquid-aerating air-jets are forced through an ordinaryperforated nozzle, (symbolically indicated at N unde a pressure somewhatin excess of the pressure normally or actually necessary to effect therequired proportionate aeration, these jets frequently operate inpractice, after the manner of injectors and thereby impart power, orenergy, to the up-flowing stream and thus produce an upward movement orvelocity of the stream in addition to the rate of up-flow due to theaeration itself. While this injector-effect or jet-action may, usually,be the cause of loss of power under the former practice. this actionnormally has a useful effect in the present system, since, by itsincrease of the range of normal action, it thereby lessens the danger ofhaving an air-lift cease operating, or becoming stalled,because of atemporary and small deficiency in the degree of said aeration. Thisuseful effect may now be *advantageously and fully realized owing to theeffective manner in which the energy of the spouting column,includingsaid I injectorefiect or energy,-is converted into pressure in theenergy-converter member, as K or K of an uptake column, as B or B. Forthis purpose said converter member should have the laterally-enclosedde-aeration column or chamber thereof, of a sufficient height, andotherwise be proportioned and have a capacity, ample for treating thenormal spouting column when this is moved up in said member, as K by adistance, or extra head, corresponding to said injectorefi'ect. Thus itnow becomes practicable to use an excess of injector-force, with anample aeration, and also to use a full measure' of submergence, therebyinsurin a more advantageous operation as a who e, since ill ing manner.

all the excess and residual energies so trans mitted can now beeffectively converted into a pressure which acts to raise thesubmergence superhead to a height compensating for these, otherwise,cumulative losses.

In this connection it will be remembered that in ordinary airliftshaving a singleli ft uptake pipe, when the aerated liquid emerges fromthe discharge-end of this pipe, the air content thereof expandsinstantly while the liquid content flows out, usually in a spurt- Thusthe de-aeration is there effected in a relatively violent manner, andwhatever kinetic energy is contained in the out-pouring liquid of thespouting column is lost, only the liquid itself being saved. Contrary tothat method and practice, in my present improvements the aerated liquidof the upflowing stream is closely retained in a columnar form or statusuntil the upfiow movement ceases and the de-aeration is completed, andat this time only the separated air is discharged at the top. while allthe liquid is returned downwardly for a distance, and then is disposedof by and in a flowing stream and without any Spurting or overflowingaction, and hence with no loss of energy consequent thereto.

Thus, by means of my present improvements, the total efficiency may beincreased by operating the primary airlift in a manner which otherwisewould result in a loss. To thus increase the efficiency of the operationin the uptake pipe B, necessarily (under the practice hitherto)increases the loss due to the discharge of an unduly large quantity ofenergy in the spouting column. But, by the conversion of thespoutingcolumn energy into a coacting pressure. that loss is retrieved,and is then made available and effective for increasing the otherwisenot efliciency of the airlift pair, and of the I multi-stage system,considered as a whole.

From the foregoing description as illustrated, it will now be seen thatin an interconnected series of three airlifts, (as in Figs. 2 and 3)each of the uptake columns has a different operative relation in and tothe system. The first said column, B initially receives the liquid, andhence may take up more or less in quantity, in a given unit of timeaccording to variations in the operation conditions; the third saidcolumn, B receives only the discharge from the second airlift, anddischarges that quantity not to be used again in the system; and, the

second said column. B operates only as one member of anairlift-transmitter intermediate to the first airlift and said thirdone, thus receiving whatever quantity is supplied to it, and deliveringonly this same quantity to said third airlift.

However, owing to the herein described interactive method of regulation,the first airlift cannot continuously over-supply the second airlift,since at the beginning of such an action, the immediate effect thereofis to check the rate of action of the first airlift and thereby preventa continuance of such an over-supply; this result, however, may bemodified to some extent, and within the range of normal workingconditions, by some degree of increase, for a brief period, in the rateof action of the second airlift. On the same principle, but in amodified manner, the third airlift normally operates to check the rateof action of the second airlift, (but in some cases to permitacceleration thereof), should the latter tend to strongly over-supplythe third air-lift.

Thus the second airlift may be restricted or regulate the rate of actionof the first one. Also the first one may be restricted in action, orreleased to act more freely, but the action of the second airlift afterthis second action has been modified by the third airlift; in the lattercase, said restriction or modification of the action of the firstairlift results from a conjoint action of an airliftpair which comprisessaid second and third airlifts of the system.

In Fig. 3, the third uptake column, B is shown elevated (above itsotherwise normal position) to a position for securing the gain equal tothe sum of the two supplemental submergence-heads 7L and [L2 of the twosubmergence columns D and D respectively, these gains being obtainedfrom the conversion,as already eXplained,-of the kinetic energy in thespouting-columns. Thus, said energy transferred to submergenc'e column Dpermits column B to be placed higher (than otherwise normal) by thepressurehead height h and, similarly, column B may be placed higher, bythe amount of head, or height 7L2.

In this connection it will be remembered that in an air-liftuptake-pipe, the up-flowing stream comprises two elements or currents,one being a liquid stream-component and this being aerated by the streamof air. This air, however, is normally in a comminuted form, or inbubbles, which not only move upwardly with the liquid stream but alsohave a further upward or floatation movement in (and relatively to) theliquid, and commonly designated as slippage. In practice, the rate,orvelocity thereof relatively to the liquid,-of this slippage of the airbubbles necessarily varies, and may arise from various causes; also therate and extent of their coalescence similarly varies. Also, thesevariations may occur from time to time, (from moment to moment), notonly in the rate of slippage, but also of the proportionate volumes ofair and liquid contained within or delivered by an -uptake pipe, andthereby produce variations in the rate of stream-flowage, and inpressures (at some points or heights within the columns), which are inthe nature of fluctuations, or, as herein considered, oscillations,either incipient, initial or resultant in character. These phenomenaalso have to be considered in connection with the normally rapidacceleration of the aerated stream during the ascent thereof within theuptake-pipe, and in accordance with a well known principle.

Thus it appears that the formation of a spouting column of aeratedliquid, takes place in connection with a peculiar changing condition ofthe mixture of air and liquid during the upflow thereof within theuptake pipe. Owing to said slippage of the air bubbles in the liquid,and the normal and well-known tendency of a stream to flow faster in thecentral portion as compared with the velocity thereof in the outer orperipheral portion, there is normally a constant coalescence of thebubbles by the combining, together of several into one, therebyincreasing their size and consequent rate of slippage, in accordancewith a well-known principle. Then, too, such a large bubble,- since itsslippage increases rapidly with its enlargement,overtakes and gathersinto itself more and more of the smaller bubbles, so that in long uptakepipes these losses may (and often do) represent a large waste, in theaggregate, of power and efiiciency. further result of that action isnormally to segregate the air more rapidly,and'with a centralizing flowthereof,-near the upper end of the uptake pipe, so that the upflowingcolumn when nearing the discharge end of said pipe may have an outerportion, or peripheral zone (as it would be seen in a cross-sectionalview of this pipe) composed of liquid nearly or fully de-aerated; thisouter portion, evidently, will tend rapidly to form and thicken aroundthe highly aerated central portion, so that on emerging from said pipedischarge-end only a moderate proportion of the total quantity of liquidmay be projected up, as a spouting column, into the converter chamber ofthe apparatus K.

Having in mind Fig. 3 and the foregoing explanations, it will now beseen that on entering the open lower end of uptake B, the liquid streamis aerated in the usual manner by air under a suitable pressure andsupplied through an aeration device, as N, (at level 4), and that beingthus aerated the stream is pushed up by submergeneeeffect (approximatelyindicated by D) toward the upper discharge-end of said pipe, at line 8,(Fig. 4). During the upflowing movement of said stream, the air-bubblesrapidly expand, and the velocity of up-flow correspondingly increasesupwardly from said point of aeration, while the pressure proportionallydecreases; also, the coalescence accelerates on nearing the said upperpipe-end, whil a substantial, or relative, de-aerating ac ion normallyproceeds in a peripheral portion, or zone, of the pipe, and thus tendsto rapidly form, or develop, a stream-segregating action, so that onreaching said discharge-end of pipe B the main-stream may be regarded ascomprising a peripheral de-aerated stream (or one of low aeration),which surrounds a central stream in which an excess of aeration has ahigh flotation velocity and is concentrating with an acceleratingcoalescence. Thus, on passing said line 8*, the said peripheralstream,this being here practically deaerated and of a uni-flowcharacter, readily passes outwardly over the pipe-end (at arrows 1' Fig.d) and thence, (as a branch-portion of the main-stream) flows directlyto the transfer conduit, P Simultaneously with that action, the newhighly aerated central stream flows upwardly (as another branch of themain-stream) in the form of a spouting column which enters with a highvelocity the top-vented column of said apparatus K and therein becomesfully de-aerated, while the liquid thereof is forced outwardly to theenclosing wall, and there is formed into a down-flow stream which on orbefore reachin said transfer-conduit re-unites with. said peripheral Astream thereby forming a restored and deaerated main-stream which flowsthrough said transfer-conduit for supplying the next followingsubmergence-column, as D Thus, it will now be obvious that in theapparatuses K, the de-aeration up-flow and down-flow stream (the latterbeing the counter-flow one) may be properly regarded as a branch-streamWhich comprises only a portion of the main-stream of liquid issuing outfrom the said upper pipe-end of column B, and of which a main,orprimary,portion which is substantially unaerated flows directly fromsaid pipe-end, and thence passes forward to the conduit port 1?, andthence into the next submergence column as a continuous uni-flowcurrent. The liquid of said branch-stream is also a stream of a uni-flowcharacter, since this liquid is only diverted temporarily from the mainstream-path, (and then only for being segregated from air temporarilyassociated therewith) and is at no time released from itsenergy-converting control, but is immediately (and in a continuingmanner) re-united with the said main or primary stream-portion, and isthen incorporated therewith into said next followlng liquidsubmergence-column.

In the upflowing fluid column within pipe B, there is normally acontinuous acceleration of the whole stream or fluid column up to line8, (see Fig. 4). In this column below line 8, the air-content of thestream accelerates more rapidly than the stream as a whole, owing to thedescribed slippage of the air bubbles in the liquid. Accordingly, it maybe said that up to said line, or level 8, there is a constantacceleration of the liquid-content, and a greater ratio of accelerationof the air-content of the stream. This relation, however, of the saidtwo velocities or accelerations, is changed when said aerated streampasses above said level 8; from this point the ascent of the air contentcontinues to accelerate while also undergoing an increasing rate ofsegregative action, whereas during this same period the upward movementof said liquid-content constantly decreases, until it finally ceases inconnection with the formation of this liquid into a counterflow stream.

In the operation of this apparatus (see Fig. 4) functioning as anenergy-converter, or as a kinetic-energy economizer, the tubular memberK, first receives (directly from pipe B), the described excess aeratedcentral stream in the form of a spouting column, together with all (ornearly all) the energy therein, reduces in succession the liquid.increment-s thereof to a state of rest, and then progressivelyincorporates them into a counter-flow stream, and later delivers this(in some or a sufficient part) through said transfer-conduit, P, tosupply, (or re-supply, as the case may be), said pressure-head insubmergence column D. Thus, it may be said that the energy dischargedout of an uptake pipe, B, with the contents of a spouting column, iseconomized, (instead of being dissipated or wasted. by being applied tothe useful purpose of increasing the pressure-head. of the submergencefor the next following airlift. This direction of the action, however,is considered as being reversed as regards the same member K of theairlift-pair member, when a particular governing action, or impulse, isinitiated from or by a next following uptake column, as B in Fig. 3.These functions, and the results thereof as regards the governingeffects, will now be described more in detail, as follows Referring toFig. 4, this enlarged and sectional view illustrates in a diagrammaticmanner a preferred arrangement of the apparatus K, and the principle andmode of action thereof, as the same are now understood. The uptake pipe,or column, B, has the discharge-end thereof terminating on the line 8*.This pipe-end 8 constitutes one channel comprised in that portion, orstructure, which is herein sometimes designated as thethree-channel-junction, and of which the aforesaid conduit or port, P,constitutes a second channel, and of which the lower portion, F, of thede-acration chamber, constitutes the third channel. These threechannels. 8*. P and F, are preferably connected by, or may comprise. 51

chamber, F surrounding the pipe-end 8 and proportioned for certaincoactive functions as hereinafter explained.

Within the opposite side-lines, 3, 3", of the tubular wall of member K,the two curved lines, 6 b are drawn for indicating a central zone Z anda peripheral zone Z Said lines b are also shown extending well down intothe pipe B, for there indicating a downward extension of said zone Zwithin a surrounding zone, Z that is wholly within uptake pipe B; inthis zone, Z the tubular or peripheral, and substantially de-aerated,upflowing stream of liquid (already described) is represented byarrowlines 1*, 1' This stream, 1, on reaching the aforesaid level 8normally flows outwardly and then downwardly, over and around thepipe-end 8', (as clearly indicated by the curved arrows at 1 T andthence flows through chamber F and conduit P, into the submergencecolumn D, as also indicated (in a customary manner) by successive curvedarrows. Said peripheral stream, 7*, being thus diverted directly intothe main flowage path of the uni-flow mainstream, the describedcentral,and now excess-aerated stream,here indicated by the single lineof arrows, 7' ,-is free to shoot upwardly through said out-turningportion, 1, of said peripheral stream and then spread out as indicatedby the outwardly-curved portions of said lines 6 6 (between thehorizontal lines 8 and 8"), and thus pass upward into the columnarde-aeration space F On thus issuing from pipe B, said highly aerated.central column, or stream, now shoots upward as a spouting column, andwith a velocity, and to a height, due to the kinetic energy therein;and, during this upward movement, the air-content rapidly expands andsegregates, while the liquid-content is correspondingly de-aerated.These operations tend to disperse said liquid outwardly,about asindicated by a series of arrows from r to r ,and thereby form of thisliquid a peripheral down-flow stream indicated by the line of arrows 1",7': these arrow lines also indicate how the said Squidcontent of thespouting column, after deaeration thereof, is formed into a peripheraland counter-flow stream which passes down ward within the walls 3, 3 andinto the space F and there re-unites with said peripheral stream, 1'from the pipe zone Z and from thence passes through conduit P into thesubmergence column D. While the spouting-column is thus flowing upward,it is continually and progressively de-aerating.

These processes being continuous (during operation of the airlift) thereseems first to be formed a de-aerated film or sheet of liquid (on ornear the inner surface of the tube) which flows down. (as indicated bysaid arrow lines r", r) with a gradually increasing thickness until itenters the passageway space at level 8 in the form of a counter-flowstream. At this time and position, therefore, the quantity of suchdownflowing de-aerated liquid corresponds with the quantity ofspouting-column liquid flowing upwardly (at level 8*) from within thedischarge end, 2, of pipe B. Thus one result of the apparatus inoperation, is to form the counter-flow and pressure-head stream equal involume per second (or unit of time) with the stream of liquid in thespouting column at the base thereof, this base being at level 8; also,to effect the de-aeration and energy-conversion simultaneously.

It Will now be evident that the primary airlift of an air-lift pair,comprises means for laterally enclosing the uptake stream, or column ofaerated liquid (when this airlift is operated with a submergence normalthereto) throughout the entire height of this stream or column, thisheight including an upper-end portion or zone which begins at the upperend of said uptake pipe, 13, and extends up to the point wherede-aeration is accomplished and upward movement of the liquid'ceases. Inthis zone, the liquid gradually separates from the air, and is laterallytransferred and formed into a new and different stream which consists ofliquid flowing downwardly by the force of gravity, and thus constitutesa counter-flow stream. And this counter-flow stream after passing downto a position where the liquid thereof is substantially free fromcontact with, or the effects of the up-spouting stream (from pipe B),may then be said to pass through the port P and enter the submergencecolumn, D, as a resisted sub-surface current, since this stream entersbelow the upper surface of the liquid submergence column, and is thusresisted by a force resulting from the head of such column, this headbeing normal y of a height between-lines 8" and 8, Fig. 4.

Thus. in the manner described in connection with Fig. 4, thekinetic-energy, or vis viva, of the spouting-column becomes convertedinto a pressure which reacts downwardly for transmission by way of afluid connection below said level 8*, and to a next following airlift.This reaction-pressure, which may also be designated as the conversionpressure,--is thus transmitted as an increment of head, which is soapplied, and this in such a direction, as to augment the normal head ofthe submergence column of another airlift-member of the system.

The height to which, in practice, said spouting column will ascendwithin the deaeration tube (or tubular chamber) as K, Fig. 4, will bethrough such a distance (disregarding friction) as will absorb, orrepresent, the amount of kinetic energy possessed by, or residing in,the aeratedfluid at the time this passes above the said level 8. Thussaid energy, or vis viva, becomes converted, and utilized in theproduction of apressure which closely corresponds with the downwardlyacting force or weight, of the spouting column, this force constitutinga reaction-pressure as already explained.

Because of this effective utilization of said kinetic energy, ,itnowbecomes economical to provide, (in said primary airlift of the pair) forthe use therein of such a volume of air in proportion to the volume ofliquid taken in at the inlet N (Fig. 3), and for supplying this air atsuch a pressure as will produce a relatively rapid upflow in the uptakepipe B, and thus (according to a well-known principle) minimize the lossof power resulting from the upward flotation, or slippage, of the air inthe liquid during the passage thereof upwardly from said nozzle or jetN, to the discharge level at.8, while correspondingly increasing thequantity of said energy as discharged in and with the spouting column.

The total head, which, in the primary uptake column, is functionallyeffective (for determining the height of the submergence in thesecondary airlift) includes the entire heightof fluid, from the lowerend at the intake level at 7 (Fig. 3), up to the topof the spoutingcolumn. Thus the weight or pressure which as a resistance has to beovercome by the submergence of the primary airlift, consists of thefluid in pipe B plus the additional weight of fluid in the spout ingcolumn within the (lo-aeration tube, K. In this total uptake head, thefluid, after being elevated by the combined action of aeration and thesubmergence, is not discharged from the upper end of said upliftdistance, but is drawn ofl' at a point (at a sub-surface position)intermediate to the submergence level and the top level of the uptakecolumn. And. in connection with a final de-aeration of the liquid. theair and the liquid,instead of being discharged together in the ordinaryway,-are now discharged separately, the air being released free frompressure (except the atmospheric pressure) and the liquid being drawnoff de-aerated and under a substantial amount of pressure in excess ofatmospheric pressure.

For more fully explaining the complex relations, and the methods ofcoaction, of the energy-converters, K, and for further illustrating theprinciples and the governing function thereof, reference is made to theseries of diagram, and small-scale, views, Figs. 4 to 4 inclusive,supplemental to Fig. 4. In each of these supplemental views, the saidapparatus is assumed to have the same detail construction andarrangement as already described in connection with Fig. 4, so that theseveral structural details thereof (so far as here shown) may berecognized without being here all desig nated by reference characters,nor again particularly described.

In Fig. 4*, it is assumed that the apparatus is operating in a uniformor balanced manner; that is, the discharge of liquid upwardly from pipeB (arrow r corresponds in volume with the down-flow of liquid ins1duncrgenre-rolumn D (arrows r) at a point below the level of thetransfer-pipe, or conduit, P. Under this condition. the stream-flow frommember K into column D. may be represented by arrows r 1'. of which thelatter, 1', turns down into column l.) for thereby indicating the courseof said flowage.

It is also assumed, in Fig. 4. that the spouting-column-head extends upto line 8 (this line representing atmospheric pressure), and thesuper-head resulting therefrom is also here shown positioned above thepath of main-stream flowage, and as extending in column D, up to thesame line, 8: this super-head, S is also indicated by shading justbelow, and extends up to, said line 8", and is now normally stationary.If, now, the submergence height in column 1), normal to uptake pipeB,-when this dis charges at line 8,be considered as coming up to saidline 8*, then it is seen that the weight of super-head S is supportedabove and pressing upon down-flowing stream S, in a manner clearlyindicated by the opposing arrows 1' and 1- which indicates,respectively, the upward resistance (arrow 1'), and the downwardpressure, or weight, (arrow 1 of-super-head 8. Thus. in Fig. 4*, thestream flowing through conduit P enters column D under asuper-atmospheric pressure equal to atmospheric pressure plus a pressurerepresented by the. height of super-head S measured upwardly from saidconduit P. i

In Fig. 4", the operations in member K, and the supplying therefrom ofliquid to column D, are assumed to be the same as above described inconnection with Fig. 4*. excepting that the down-flow of the liquidsubmergence-column S has been accelerated to the extent .of taking thesame quantity through conduit P and also drawing down some liquid fromthe super-head.-here designated by S -until this super-head has been.lowered from said line 8 down to the level 8; this head-loweringmovement is here indicated by arrow r". An immediate and normal effectof thus lowering said superhead is to reduce the pressure-resistance tothe described stream-flow through conduit P; and. if this reductionshould he continued for more than a relatively momentary period. thespouting-head height. in converter K, would be lowered by an it raising)of the surface level of the submergence super-head as above described.may readily occur in practice from various causes; as, for instance,from a stopping up of one or more holes in the liquid-aeration means. oras a result of some abnormal but temporary action in one of theairlift-members of a series of them. One such cause, usually quitetemporary. may be an unusual degree of coalescence and the excessiverate of slippage consequent thereto.

In Fig. 4.said reactionary movement,- for restoring super-head S .isrepresented as having taken place. Assuming that the spouting-column(arrow 1") has a pressurehead extending up to line 8, that, at the beginning. the super-head corresponds with S Fig. 4", and that thedown-flow velocity of the stream (arrow r) in column D has been somewhatreduced, then the flow through conduit P naturally divides. the mainportion.-as before.-flowing down (arrow 7") into column I), while asmaller portion flows upwardly (arrow 1'") to resupply the submergencesuper-head. here designated by S In this manner, the lowcred head. 3 ofFig. 4 is gradually (usually rapidly) raised from said line 8" up toline 8 .-as in Fig. 4,and, under the action of the forces and inertiasthen appertaining to the apparatus and the streams therein. the level ofthis super-head. S will normally be carried up to a higher level. hereindicated by line 8 At this height. 8". the added weight tends to againaccelerate the down-flow velocity of the submergence stream (arrow 7").and thereby again draw down the super-head level toward line 8. therebyrestoring the status represented in Fig. 4. and already described. Thusthe described range of suecessive hea ds. from line 8" to line 8". mayhe said to constitute an oscillation in the operation of the apparatuscomprising the energy-converter. K. and the upper portions of thecolumns B and D directly associated therew th. including the upper-endportion ofcolumn D which is the superhead container.

Tn practice. of course. the vertical extent of said oscillationsnecessarily fluctuates,

and these oscillations also occur with a variable frequency, dependinglargely upon the coaction therewith of operations simultaneouslyoccurring in more remote portions of the system. Also, it will now beevident, the rate or rapidity of said action or movement for therestoration in height of a lowered supplemental head, as S depends inpart upon the relative cross-sectional area of column D, so that bymaking this member somewhat larger than tube B, said rate ofhead-restoring action may be regulated, (within such limits as may befound desirable, in any particular instance), for inaugurating anacceleration of upflow in pipe B (by decreasing the columnhead-pressureresistance thereto) at a moment,or instant,slightly before said processof headrestoration can normally be completed. This over-lapping of thesaid two functional and successive but distinct operations, is deemed tobe desirable as tending to restrain a too great, or a too rapid,lowering of the effective head of the spouting column while assistingthis column by a raising thereof, (by a transference of liquid andpressure), and thus continue to completion the raising of said loweredsubmergence head up to the full normal height thereof.

Thus the apparatus when organized and aranged as set forth, provides fora highly sensitive mode of interaction which operates as a quick-actinggovernor, and thereby provides for limiting the oscillations of flowage,and of heads and pressures, in a most effective manner. And. theapparatus may be said to be also organized for regulating an interveninggoverning action by means of a supplemental-head chamber connected fordirect coaction with the spouting-head during a time-interval followinga change of flow in one uptake column, and prior to a resultant but inpoint of time, later and responsive uptake flow in the other saidcolumn, for thereby reestablishing without violent agitation, a balanceof and between the operations therein.

Thus, in the time between an initial acceleration of upfiow in column D,and a corresponding or ultimately-resulting increase of upflow velocityin pipe B, there has been an intervening governing-action consisting inthe instant lowering of said head S followed at once by a partialrestoration thereof. Thus said initial lowering of head S and theinaugurating of the restorative operation therefor, maybe said to bepreliminary to, and in point of time to functionally precede, thebeginning of the ac celeration of flow in pipe B for producing a newlydetermined balance as between the flowage in columns B and D.

A further feature of this series-system relates to means,ap urtenant tothe primary airlift and the submergence container, or

column, of a secondary airlift,proportioned for receivin and de-aeratingthe aerated liquid of said spouting column and for then distributingthis liquid, each of these operations being continuous during theoperation of the airlift pair. Said distribution is effected in apeculiar manner, being delivered (from time to time as required) invariable relative quantities, or proportions,according to inequalitiesin the operation of the two airlifts,in part to the upper end of saidmain submergence head (this end being at line 5*, Fig. 4), and in partto the lower end, (at line 5, Fig. 4), of the supplemental submergencehead, (as S Fig. 4) which extends upwardly from said main submergencehead.

This interactive operation of two said airlifts under said variabledistribution of liquid from the spouting-column, operates in connectionwith the described oscillation of flowage and pressure naturallyoccurring in the uptake pipes and conduits, as a factor in that jointoperation of the airlift pair whereby a non-normal operation whetherarising in one or the other of the two airlifts, is transmitted andcounteracted or balanced, for thereby and at once re-stabilizing anormal operation of the system following the occurrence therein of manymaterial inequalities in the operation of the two airlifts.

An important feature and advantage of, and one which furtherdistinguishes,tliis uni-flow multi-stage system, consists in itscapacity, on being subjected to certain irregularities as regards theair-supply and other conditions, for operating temporarily in areverse-to-normal manner, and for then automatically starting, orresuming (as the case may be) its normal and forwardlyacting mode of oeration. For instance, in pract1ce,especial in certain mining regionshavin worklngs diflicult of access,- it has now become commerciallyimportant sometimes to supply the air through very extended pipe-linesfrom compressors located in valleys far below and Where waterpower isavailable for use in compressing the air by steam-power.

In such pipe-lines, however,even when these lines are quite moderate inlength,- water is liable to collect at one or more points therein,fromcondensation or otherwise,and be carried forward in a violent andoscillating manner with the result of making the air-supply and itspressure fluctuate extremely at the nozzles of the air-lift system. Somewater, in such an instance, may be carried forward to one nozzle and forthe moment completely block the operation thereof, while, at the samemoment, air may be forced through one or more other nozzles under anexcess pressure, and thereby force air backwardly (through a lowercolbers,-prepares umns-connection) and thence upwardly into asubmergence column. I

This reverse-to-normal and temporary mode of operation, is brieflyillustrated, but only in a diagrammatic manner,in Fig. M. In this view,the liquid stream in column D is indicated (arrow 1'") as having beenreversed, and as having been driven up (arrow 1') to form a highlyelevated pressure-head, S, which serves to temporarily store up aconsiderable quantity of liquid, while applying a heavy resistantpressure at the level of conduit P. \Vhen said head S has been raisedhigh enough to fully resist the normal flow (arrow 1*", Fig. 4) from themember K, then a portion of the liquid flowing up in column D (at arrow1-), will naturally be diverted (arrow 1*), and pass through conduit P,flow (arrows r") up into the de-aerating chamber of converter K, andthereby reach a point so far above line 8', as to press back (see arrow1' the normally rising stream (arrow 1") in uptake pipe, B, and thus fora time stop the operation of this pipe as a liquid-supplying means,-this being here indicated by the opposing heads of arrows 1" and 1-within said pipe B. On this status of the flowages being continued for atime, the normal up-flow in pipe B may be chan 'ed to a down-flow, andthereby deliver liquid (supplied upwardly through column D) into thesubmergence column of pipe B. Thus, said back flow, if sufficientlycontinued or extensive, tends to conserve the contents so displaced, byshifting the same backwardly in the system, stage by stage, as far asmay be required for the storin thereof, and thereby avoids a reductionof the liquid content of the system as a whole.

When there occurs a sudden back-flow of excess-pressure air, (aselsewhere herein explained) this back-flow normally operates toover-aerate the lower-end portion, and thereby raise the whole quantityof the liquid of said submergence column, but only to a height much lessthan the same uantity of air would normally raise the liquid in anuptake column, since the cross-sectional area of the submergence column(as herein illustrated) is made considerably greater than thecross-sectional area of the uptake column. This feature, andrelationship, is deemed to beparticularly important. since it favors abackward flow of liquid through successive air-lift systemmembers, andthereby,thr0ugh themaintenance of a full suppl for these memthem orautomatically starting to act in a forward direction at once on theair-supply subsiding to a normal pressure extending equally to all theaeration devices of the series. 1

Thus the present'system under normal conditions operates to forwardlyactuate the stream by the uni-flow method, and under the describedoccasional and abnormal conditions, operates backwardly in a mannerwhich, besides conserving the liquid contents, by a storing thereof,enables the system to immediately resume its normal operation on arestoration of a normal airsupply. Thus it may be said that the several.air-lift system-members are not only inter-regulative as regards theirforwardlyacting functions, but also are inter-acting andinter-regulative as regards and during a temporary reversal of theirnormal mode of action, for thereby makin the s stem self-starting andself-regulating un er a wide range and variety of opposing conditionswhich otherwise would normally halt or defeat the operation thereof.

An analogous situation as may arise from the described use of saidpipe-line air-supply, may also arise in some instances from othercauses, as for instance, when the compressors are located near theair-lift system, and especially when, in this arrangement, thecompressor is actuated electrically by conductors bringing the electriccurrent from distant power plants. In the latter case, as is well-known,the power lines are subject to surging effects, thereby varying theaction of the motors and compressor; and this, in turn, may suddenly andmateriall '(even if only temporarily) change t e effective relation ofair-supply to the normal requirements of the air-liftsystem. Suchvariations may frequently be sufficient, in practice, to disarrange theoperation of a multi-stage air-lift, unless overcome instantly bycounter-acting forces; this is accomplished in the present system by thedescribed capacity thereof for a re verse-to-normal mode of action, andfor the automatic resuming of a normal forwardl acting mode of action,and by having tli e described inter-regulative function effective undereach of these relatively reverse modes of action.-

In this connection, it should also be pointed out, that the continuityof operation maybe disturbed, or in some instances suspended, as theresult of .accidental causes, especially in mines and uarries, and incertaln industrial plants. or instance, the water-supply may be changedin character, or in specific gravity, by the incorporation therein ofdust or silt, or it may become impregnated with gas, or gas-forming.materials, in. one (or a few) of the submergence-columns; this latteraccident might so reduce the submergence-effect at one or more points,as to prevent the coacting aeration from producing a forward flowage ofthe liquid in the system. Also,

es eciall in certain wet mines one of the P y a columns may .be suddenlyflooded from above, thereby over-charging a submergence column, or anenergy-converter, or both, to the extent of halting the operation of theentire apparatus. In these and other ways, either a single air-lift or aseries system,

may be stopped; but in the present system,

this has the unusual capacity, as already explained, of normally beingself-righting, and self-restarting upon the subsidence or removal ofsuch an interrupting cause, and

of thus resuming operation in a normal and self-continuin manner.

A further eature of improvement in the airlift pair, and in theoperation thereof, is

more clearly indicated in Fi 3, this View being analogous (in the main)to Fig. 2.

Assuming the apparatus to be operating regularly, and with thesupplemental submergence head maintained at rest,as described inconnection with Fig. 4 ,then, it

is evident the upflow stream into secondary uptake pipe B must be justequal in quantity per unit of time, to the flow through port P into themain submergence container, or column D If, now, the rate of 2.5 flowageof said stream into pipe B should be accelerated as a result of a changeof action in pipe B ,as may readily and often occur for reasons alreadystated, this instant increase would naturally have the effect (at leastmomentarily) of reducing the effective pressure in the entire length ofsuch stream, and would thus instantly decrease the opposition of thisstream and its pressure to a more rapid inflow through said port P Thusan increase of flowa e velocity in one pipe instantly and normal ydecreases the resistance to the stream flowing thereinto; and thisresult is deemed to be one of the most important of the interactivefunctions of any pair of coacting airlifts. The said intermediateuptake-column, B, has a special relation to the next preceding and tothe next following air-lifts, (see Fig. 3) in that the up-fiowing streamin B is not only elastic, but is coactive between, and subject to theconstant restraint of, two nonaerated liquid down-flowing streams eachof which is in communication with said elastic stream at positionstherein which are under the pressure of a constant head of forward,direction; and these inertia resistances are coactive with each otherthrough sald elastlc stream being intermediate thereto. At the same timesaid downflowing stream (in column D), is coactive with and intermediateto the two upflowing elastic streams in columns B and B, so

that in the said coaction of the streain in column D with the elasticstream in column B this stream in column D so acts after being modifiedin its (otherwise normal) action by its said coaction with the elasticstream in column B Thus the total coaction as regards either saidstream, is of a composite nature, and comprises coactive efi'ectsappurtenant to several and different pluralities of column streams,which operate concurrently.

Thus it may be said that in the more extended developments of thepresent invention, there is a multi-lift system of airlift elementsconnected for uni-flow operation, and comprising successive (two ormore) of the column-pairs, through which the liquid stream is not onlycontinuous, but is subjected to the controlling effect,-at each saiddown-turn portion thereof,of a constantlyacting super-head pressure.These columnpairs, as B and D or B and D (Fig. 2 or Fig. 3), may thus besaid each to be topconnected by an economizer-regulator, since theconverter, as K, economizes the residual energy of the upflowing aeratedstream, and thus, also, is coactive for providing the head required foruse in effecting the interactive regulation, and thus effect theauto-governing.

A further and special purpose of said upward extensions of the columnsD, is to provide a head of 1i uid which is not located directly in thepat ofthe stream, (see Fig. 4), but is so joined to and above suchstream-path that this head of liquid constitutes a suflicient reserve orsupply to which liquid may be added from below, (by an under-feedmethod), and from which liquid may be withdrawn, in and for theinteractive regulation of the successive airlift'ele- 'ments, andwithout materially affecting either the continuity or flowage of theliquid in its said path nor as a unifiow stream, nor theplus-atmospheric pressure under which this flowa e takes place in saiddown-turn portions t ereof. Thus the stream considered as a whole,and onthe occurrence of, variations in the operation thereof,may

have applied instantly thereto, a force and.

a liquid-supply (drawn from one or more of said reserve heads) tendingto supplement or to counteract s uch stream-variations and therebyrestore a regulated and normal flow.

A further feature of the inter-regulativc functioning, relates to theeffects produced on the inflow of air through nozzles N, by the varyingmomentum's and 'inertias of the down-flow streams in columns D, whereby,at certain momentsand under the varying conditions of the, connectedup-flow streamsin columns. B,-the rate. of the air supplied through onenozzle may be changed for the moment and in an automatic manner, and

\ tions occur simultaneously at successive thus become directlyco-active in relation to the governing of the operation of the system.In an extended multi-stage system, those air-flowage variations mayoccur in one portion of the series to increase the airsupply of oneuptake-stream, while in another portion of the same series of airlifts,the supply of air through the nozzle of another uptake column may bedecreased; or, such increases,or decreases, as the case may be,may occursimultaneously at such different positions in the series.

For instance, when there is an increase of pressure in column D (seeFigs. 2 and 3) while the pressure in column D remains stationary (forthe moment), the normal effect is to apply more pressure to the lowerend of the stream entering column B and thereby somewhat increase theresistance to the in-flow of air through nozzle N And, should thepressure-resistance in column D be suddenly reduced, while no increaseof pressure should then occur in column D, a normal result would be topermitg for the moment, an increased flow of air through said nozzle N3,and thereby, also, aid (both. directly and indirectly) in restoring abalanced operation of the whole system. Such changes, occurring at anypoint in the system, tend instantly on beginning, to modify the pressureor rate of action at adjacent points and thereby counteract theotherwise disturbing effect of such a change from the normalv balance,and thereby aid in securing an interactive regulation as a result of thereciprocal and peculiar coaction elsewhere herein more fully described.

Since, as above pointed out,-a variation from auniformity of functioningat any one of said points of the regulative action, operates bytransmissionof the effect (of such Variation) in a forwardly and also ina backward direction,and this at the same instant,-therefore, when twosuch varia- O- sitions, respectively, in the system, all t at portion ofthe system which is intermediate to the. said locations of thevariations, is subjected to a plurality of the transmitted regulativeinfluences, or effects, with the result that the completeregulation,.-when any is needed at any place or instant',is of a complexnatuie, and is accomplished in such a prompt and eflective maimer as toinvolve only a relatively small change in any oneof the super-headcolumn-increments. And, in such a complex regulative operation, orfunctioning, when a variation of action occurs in one uptake-column(exceptthe primary one), this action is transmitted, or

reacts, through the directly coasting sub-- mergence column and thustends to reyerse-f ly modify the super-head or column-increment whichserves as the supply-means in the regulation of the pressure-head ofthis submergence column.

It will now be evident how the describe graduation of the transmittedregulative effects, from a variation-inaction occurring initially at aposition above midway in an extended system,-especially When'thenum' herof airlift-members exceeds three or four,has the important feature ofgradually reducing the extent of the interaction in passing through sucha series, until the total-effect becomes distributed in a manner tendingto produce a restoration of a completely balanced action throughout theseries, including the airlift-member in which the variation first arose.Another valuable result is that when two (or any plurality of) suchvariations occur simultaneously, or nearly so, at relatively distantpoints,- (or originate in non-contiguous airlift-members), the resultantseries of transmitted variations may blend together (as transmitted toand appearing at intermediate points) and thus be more quicklyneutralized, and become coactive more quickly and fully in effecting therequired balancing of the operations of each airlift-member, and of thesystem as a whole. And this equalization of said variations andtransmitted effects is further favored by the described delaying (owingto the time intervals required therefor) of the successive said effects,so that any plurality of such initial variations-ofaction become rapidlyrestored by the described intcraction, this normally proceeding bothforwardly and backwardly in the series of airlift-members, from each ofsaid initial variations.

Owing to the described transmission,- forwardly and backwardly in asystem comprising two or more of the airlift-members,of the said initialvariations-ohm:- tion, and of the said regulative actions forcounteracting the same, it will be evident that each of saidairlift-members shares in the operation and functioning of the member ormembers which are next thereto in the system, so that in the connectedseries of such members, none.of them can be said to operate alone, or asan independent, or single, airlift. Thus the systemhas the character ofa unitary apparatus, and as one arranged for performing and effecting asingle operation and result, this being to elevate the. liquid throughthe entire distancerequired and by a uni-flow stream having therein nopoints of disconnection, regardless of the number of times,during suchtotal lift,this stream shall be subjected to the forwardly-impellingpressures, or to. the successive aerations and de-aerations whereby saidpressures (or submergence-effects) maybe produced and applied thereto.For these purposes, the successive means,as for instance, the conduitformations,for aeration and de-aeration of the liquid should be soplaced and proportioned that the aggregate force thus exerted on thestream will correspond in .power to the height the liquid is to belifted in passing from the intake point up to the point of final streamdischarge.

In ordinarypraetice, as is well-known, the kinetic effect of agiVensubmergencehead in pushing up an aerated liquid column in aconnected uptake pipe, is directly alfccted by any variation in theresistance to up-flow of said aerated column. This resistance, as alsowell-known, ordinarily and normally varies in a fluctuating'mam ner, sothat the resultant uptake flowagemay be described as normally having awave-like action, and this result may occur,

or accrue, with a varying degree of 'force,

and with a variable periodicity. One cause of those variations isunderstood to arise from a fluctuation in the rate of coalescence, andthe consequent enlargement of-the size of the air-bubbles in theHP-flOWlXlg aerated column so that any abnormal increase of thecoalescence, even momentarily, thereby increases the velocity of theupfiow, or floation rate, ofthe bubbles in and relatively to theupflowing liquid content of the aerated column. g

These wave-like variations may occur, in the present multi-stage system,simultaneously in two or more of the uptake-columns, or' they fimyjoccur therein in alternation, 0 that two of said kinetic resistances mayoccur in two successive uptake-columns at the same-moment and therebyapply to the uni-flow stream a double resistanee-effeet; and, at anothermoment, an increased resistance may occur in one said columnsimultaneously with a decreased resistance occurring in another saidcolumn. 1 Thus, in the operation of the system as a whole, one saidaction may for the moment either counterbalance. or supplement theother, so that these actions may be said to become coactive each withthe other.

A well-known objection to the use of uptakecolumns of eat length, arisesfrom the lar ratio 0? increase in the volume of a bu ble in passingupward therein, due to the great range of pressure to which such bubbleis thus subjected, and since the slippage also increases with theincrease of diameter of the bubbles, the loss normally arisin from thiscause is in itself a considera le one, "besides causing an increasedamount of coalescence. This latter result is often, a' serious one, thefrequent but irreggmh r combining of two or more bubblesintoone,"operates .unduly to increase the volume of a bubbleand .henceto furtherincrease, the rate of the slippage, as well as to. accelerate.the velocity} of the upentire length (height) of the uptake column.

By using onl relatively low lifts, and a sufiicient num er, or series,of-these multilift stages for raising the liquid to a given elevation,not only are the pressure changes brought within a smaller range, andthe slippage reduced in quantity and velocity, but a relatively greaternumber of spouting-column energy-conversions are obtained in a givenheight.

This feature and advantage is deemed to be of special importance, sincein such a lower-pressure system the aggregate of surface-contact betweenthe air-content and i the water-content of the upflowing column is muchgreater in pro ortion to the relative quantity therein 0 free-air, sothat a relatively large ratio of heat transference,- within practicablelimits,can now be economically obtained, and this in connection with a'minimizing of the well-known initial loss of heat due to the describedaircompression and radiation.

Usually the heat developed in the airsupply uy its compression isnecessarily lost by radiation before this air can be incorporated (inthe form of bubbles) into the lower end of the aerated. up-take column,so that, at this'lower' point (or level), the air and water are ofsubstantially the same temperature. During the movement of the bubblesupwardly from said lower level, the air thereof continuall becomes*cooler by reason of their expansion, andthis loss of heat is graduallyand largely compensated by the transference by conduction of heat fromthe water to the air by means of said surfacercontact of the bubbleswith the water.

These combined gains and advantages are also obtained, in the presentsystem, in connection with a further advantage and result which isdeemed to'be of special importance as regards. I the inter-regulative

